Jesse Whitehouse Developer | Analyst

Completing the W-4 When Married, Filing Jointly

If you're uncertain how to complete your own W-4, please speak with a qualified tax advisor.

For all our moaning every April about the feds stealing our hard-earned dollars, it seems like everybody loves tax time. Sure, it’s a headache preparing the forms and all that. But it turns out we mostly enjoy the dopamine surge when our tax return clears. I’ve never had the pleasure, actually, because I adjust my W-4 each January to tie my bi-weekly withholdings to my year-end tax burden. This usually works great - but I overshot last year. I under-withheld around $2,000 by claiming too many allowances. Ouch. Spurned but not deterred, I conservatively adjusted my W-4 in 2015 to increase my pay-period withholdings. I didn’t expect a large payday this time around; but I was looking forward to an easier go of things in my 2015 taxes.

No such luck.

When we filed our returns this year, my wife and I found a nasty surprise. A $3,000 shortfall out of nowhere. We redid TurboTax from scratch. Three thousand clams. We double-checked with an online calculator. One…two…three large. We even dug out the tax tables and calculated everything by hand. We definitely owed the money. “How did this happen?” we asked.

We misunderstood the tax code. That’s what. Have a look at the tax table below. This shows the marginal tax brackets for married couples filing jointly in the year 2015.

Tax Rate Income
10% $1 to $18,450
15% $18,451 to $74,900
25% $74,901 to $151,200
28% $151,201 to $230,450
33% $230,451 to $411,500
35% $411,501 to $464,850
39.6% $464,850+

If my wife and I both make $20,000 this year, our incomes individually each fall in the 15% tax bracket. The first $18,450 at 10%, the remaining $1,550 at 15%. That’s $1,845 + $232.50 = $2,077.50. Since there’s two of us we’d double that, for a total tax of $4,155, right?

Wrong. Since we file jointly, our incomes are combined for taxation purposes. At $40,000 we’re still in the 15% tax bracket but more of our income is taxed at that rate. And the math looks more like $1,845 + ($21,550 x 15%) which works out to $1,845 + $3,232.50 = $5,077.50. That’s a $922.50 difference, almost a thousand dollars, on a technicality.

Though I’ve changed the numbers in the above example, this is exactly what happened to us. It was a dumb mistake. But in retrospect we walked into a well-hidden trap. The IRS tax withholding tables are nifty tools but they aren’t designed for people in our situation. The typical single-income breadwinner can fill out a W-4 in 30 seconds. Add up all your dependents, add yourself and your spouse (if you have one), sign at the bottom and move along. At the end of the year you’ll get a small refund and you’ll be on your merry way.

Multi-income households like mine are in a different boat, however. Since my employer doesn’t know my wife’s salary or vice-versa, they can only withhold income consistent with my individual projected tax rate. And if they do that, in the above example, I’d be short $922,50 at tax time. The only way to avoid this shortfall is if I instruct them differently. And that’s where form W-4 comes in.

Step by Step

Two earners or multiple jobs. If you have a working spouse or more than one job, figure the total number of allowances you are entitled to claim on all jobs using worksheets from only one Form W-4. Your withholding usually will be most accurate when all allowances are claimed on the Form W-4 for the highest paying job and zero allowances are claimed on the others.

This note appears at the top of Form W4 on the IRS website. Don’t miss it. And if you need help filling it out, check out Pub 505 for deeper instructions. The key part here is that form W-4 has two pages. The second page has a whole worksheet for married couples filing jointly. Using the example above, here’s how to use it:

Important! Use the instructions below to complete the W-4 for whichever spouse has the higher salary. The lower salary W-4 will simply claim zero allowances (enter 0 on line H and sign at the bottom).
  1. Calculate your normal withholding using lines A through G on page 1 of Form W4. Enter the total on line H and move to page 2.
  2. The Two-Earners/Multiple Jobs Worksheet helps you calculate how much additional should be withheld from your checks to ensure you don’t under-withhold. Enter your total from line H onto line 1 here.
  3. Have a look at Table 1, it looks something like this:

    Wages from lowest paying job Enter on Line 2 Above
    $0 to $6000 0
    $6001 to $14000 1
    $14001 to $25000 2

    Enter the number corresponding to the lower salary and enter it on line 2. Subtract line 2 from line 1.

    This is important

    • If line 1 is greater than or equal to line 2, enter the difference on line 3 here and page 1 line 5. This replaces the calculation you made in step 1. If you claim this number of allowances, the withholdings from this paycheck will cover your tax burden as long as your spouse’s W-4 claims zero allowances.
    • If line 2 is greater than line one, you have more work to do. Enter 0 one line 3 here and on page 1 line 5. This means that if you and your spouse both claim zero allowances on your W-4’s, you’ll still have a shortfall at the end of the year. Proceed to step 4.
  4. You’re on this step because page 2 line 2 is greater than page 2 line 1. For this step, subtract the larger number from the smaller one. Enter this on line 6. Now look up the higher of your two salaries on Table 2, it looks something like this:

    Wages from highest paying job Enter on Line 7 Above
    $0 to $75000 $610
    $75001 to $135000 $1010
    $135001 to $205000 $1130

    Enter the number corresponding to the difference onto line 7.

  5. Multiply line 6 times line 7. The product is how much additional tax you’ll need to withhold from your checks to cover your tax burden assuming you and your spouse both claims zero allowances. Lines 8 and 9 are used to calculate how much additional should be pulled from each check. Once you’ve calculated the correct amount per check, enter it on page 1 line 6.

  6. Sign form W-4 and return it to your human resources department.


In my example, my wife and I make the same salary. In this case, it doesn’t matter which of us has additional money pulled from our checks, so we’ll say that she’s claiming 0 allowances and I’ll have the additional pulled from my check. So let’s walk through the steps:

  1. My normal withholding is 1. Now I could claim 2 (one for me and one for my wife) but the W-4 instructions say explicitly:

    Enter “1” for your spouse. But, you may choose to enter “-0-” if you are married and have either a working spouse or more than one job. (Entering “-0-” may help you avoid having too little tax withheld.)

    I enter 1 onto line H.

  2. I enter 1 onto line 1.
  3. On Table 1, the lower income is between $14001 and $25000. So I enter 2 onto line 2. In this case line 2 (2) is greater than line 1(1). So I enter 0 on page 1 line 5 and move on to step 4.
  4. I subtract the larger number from the smaller 2 - 1 = 1 and enter that on line 6. On Table 2, the lower income is between $0 and $75000. So I enter $610 onto line 7.
  5. I multiply line 6 by line 7. That works out to $610 * 1 = $610.

    This means I need to withhold $610 more throughout the year in addition to my wife and I both claiming zero allowances. I have 22 more checks remaining this year. SO I need to have an additional $610/22 = $27.72 withheld from each check. I enter $27.72 on page line 6.

  6. I sign and return this to my human resources department.

A Final Note

Despite the gravity of our tax bill this year, we’re in a good position to cover it. We have an emergency fund for situations just like this. But it’s worth noting that things could have been much worse for us. We’re blessed in that we only owe additional taxes - but we were awfully close to owing penalties in excess of our tax bill. That’s because the IRS doesn’t like it when people habitually under-withhold towards their income taxes. In fact, you can be assessed a penalty if the tax you withheld in the current tax year is less than 90% of your total tax liability in the prior year.

So for example, if you owed $10,000 in taxes in 2014 and you under-withhold for your $12,000 tax bill in 2015, if your actual 2015 withholding is less than $9,000, you’ll owe a penalty to the IRS. Thankfully, we dodged that bullet.

To be safe, I’ll be checking our pay stubs in July to make sure that our tax withheld so far ties to our overall tax rate for the year. If your in a similar situation, I suggest you do the same.